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U.S. 50 Corridor EastTier 1 Draft EnvironmentalImpact Statement

Air Quality

Technical MemorandumJune 2016


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U.S. 50 Corridor East Tier 1 Draft Environmental Impact Statement Air Quality Technical Memorandum

June 2016 i

Table of Contents

Chapter Pages

1. Project Overview ............................................................................................................................ 1

2.

Resource Definition ....................................................................................................................... 2

3. Applicable Laws, Regulations, and Guidance ............................................................................ 3

3.1. Clean Air Act of 1990 ....................................................................................................................... 3

4. Methodology ................................................................................................................................... 5

4.1. Relevant Data or Information Sources ............................................................................................. 5

4.2. Data Collection and Analysis Methodology ...................................................................................... 6

4.3. Project Area...................................................................................................................................... 6

4.4.

Effects .............................................................................................................................................. 7

4.5. Mitigation Options ............................................................................................................................ 7

4.6.

Deliverables...................................................................................................................................... 7

5. Existing Conditions ....................................................................................................................... 8

5.1. Climate ............................................................................................................................................. 8

5.2. Air Quality ......................................................................................................................................... 8

5.3. Traffic Conditions ........................................................................................................................... 11

6.

Effects ........................................................................................................................................ 13

6.1.

No-Build Alternative ....................................................................................................................... 13

6.2. Build Alternatives ........................................................................................................................... 13

7. Mitigation Strategies .................................................................................................................... 17

8. References .................................................................................................................................... 18

Appendices ........................................................................................................................................ 21

Appendix A. Resource Methodology Overview for Air Quality...................................................... 23

Appendix B. Abbreviations and Acronyms...................................................................................... 25

Appendix C. National Ambient Air Quality Standards .................................................................... 27

Criteria Pollutants ....................................................................................................................................... 27

National Ambient Air Quality Standards Compliance (Attainment vs. Non-Attainment) ............................ 28

TablesTable 5-1. Air Emissions Inventory for Pueblo, Otero, Bent, and Prowers Counties by Source Category(2004) .................................................................................................................................................................9 Table 5-2. Monitored Values Summary for Pueblo and Prowers Counties ..................................................... 10

FiguresFigure 1-1. U.S. 50 Tier 1 EIS Project Area .......................................................................................................1


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Figure 5-1. Average Annual Daily Traffic on I-25 through Pueblo and on U.S. 50 in the Lower ArkansasValley (2011 and projected 2040) ................................................................................................................... 11 Figure 6-1. Build Alternatives Overview .......................................................................................................... 14


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1. Project Overview

The U.S. 50 Corridor East Tier 1 Environmental Impact Statement (U.S. 50 Tier 1 EIS) was initiated by theproject’s lead agencies, the Colorado Department of Transportation (CDOT) and the Federal Highway Administration (FHWA). The purpose of the U.S. 50 Tier 1 EIS is to provide, within the framework of the

National Environmental Policy Act of 1969 (NEPA), a corridor location decision for U.S. Highway 50 (U.S.50) from Pueblo, Colorado, to the vicinity of the Colorado-Kansas state line that CDOT and the communitiescan use to plan and program future improvements, preserve right of way, pursue funding opportunities, andallow for resource planning efforts.

The U.S. 50 Tier 1 EIS officially began in January 2006 when the Notice of Intent was published in theFederal Register . The U.S. 50 Tier 1 EIS project area (.

Figure 1-1) is the area in which U.S. 50 Tier 1 EIS alternatives were assessed. This area traverses ninemunicipalities and four counties in the Lower Arkansas Valley of Colorado. The nine municipalities include(from west to east) the city of Pueblo, town of Fowler, town of Manzanola, city of Rocky Ford, town of Swink,

city of La Junta, city of Las Animas, town of Granada, and town of Holly. The four counties that fall within thisproject area are Pueblo, Otero, Bent, and Prowers counties.

The project area does not include the city of Lamar. A separate Environmental Assessment (EA), the U.S.287 at Lamar Reliever Route Environmental Assessment , includes both U.S. 50 and U.S. Highway 287 (U.S.287) in its project area, since they share the same alignment. The Finding of No Significant Impact (FONSI)for the project was signed November 10, 2014. The EA/FONSI identified a proposed action that bypassesthe city of Lamar to the east. The proposed action of the U.S. 287 at Lamar Reliever Route Environmental Assessment begins at the southern end of U.S. 287 near County Road (CR) C-C and extends nine miles toState Highway (SH) 196. Therefore, alternatives at Lamar are not considered in this U.S. 50 Tier 1 EIS.

Figure 1-1. U.S. 50 Tier 1 EIS Project Area


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2. Resource Definition

The U.S. Environmental Protection Agency (EPA) sets standards for the amount of certain pollutants thatcan be in the air before they become harmful to public health and the environment. Air quality is measuredby the amount of these pollutants in the air when compared to these standards.


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3. Applicable Laws, Regulations, andGuidance

In addition to adhering to NEPA and its regulations (23 Code of Federal Regulations [CFR] 771), the Council

on Environmental Quality (CEQ) regulations (40 CFR Parts 1500-1508), and the Moving Ahead for Progressin the 21st Century Act of 2012 (MAP-21), regulations and guidance provided within the Clean Air Act of1990 (CAA) also were followed during this analysis of air quality.

3.1. Clean Air Act of 1990The Clean Air Act of 1990 and its associated regulations are the basic federal statutes and regulationsgoverning air pollution. The provisions that are potentially relevant to this project are the National Ambient AirQuality Standards (NAAQS) (CAA 2003, part 50), the transportation conformity rules (CAA 2003, part 93),and mobile source air toxics (MSATs). Each of these provisions is discussed below.

3.1.1. National Ambient Air Quality Standards

The Clean Air Act of 1990 requires the EPA to establish NAAQS for pollutants considered harmful to publichealth and the environment (CAA 2003, part 50). Primary standards set limits to protect public health,including the health of “sensitive” populations, such as people with asthma, children, and the elderly.Secondary standards set limits to protect public welfare, including protection against decreased visibility anddamage to animals, crops, vegetation, and buildings.

The EPA has established NAAQS for six principal pollutants, which are called “criteria” pollutants. They arecarbon monoxide (CO), nitrogen dioxide (NO2), ozone (O3), lead (Pb), particulate matter with particlediameters of 10 microns or less (respirable particulate matter) (PM10), particulate matter with diameters of2.5 microns or less (fine particulate matter) (PM2.5), and sulfur dioxide (SO2). The NAAQS are summarized in Appendix C.

3.1.2. Transportation Conformity Rules

The transportation conformity rule focuses on the conformity of transportation plans, programs, and projectsthat are developed, funded, or approved by the U.S. Department of Transportation and by metropolitanplanning organizations or other recipients of federal funds (CAA 2003, part 93). These regulations set forthpolicy, criteria, and procedures for demonstrating and assuring conformity of such activities to an applicableimplementation plan developed pursuant to the Clean Air Act of 1990. A determination of conformity is madeby the metropolitan planning organization and the U.S. Department of Transportation.

The transportation conformity regulations of July 2004 require that transportation projects that are regionallyimportant, federally funded, or both demonstrate transportation conformity to state implementation andmaintenance plans. These regulations require that the project:

Be included in a fiscally constrained regional transportation plan,

Be included in a fiscally constrained transportation improvement plan, and

Not cause or contribute to any new or existing violations of NAAQS.

3.1.3. Mobile Source Air ToxicsIn addition to the NAAQS, the Clean Air Act of 1990 requires the EPA to regulate air toxics. MSATs are asubset of the air toxics defined by the Clean Air Act of 1990. MSATs are compounds emitted from highwayvehicles and non-road equipment. Some air toxic compounds are present in vehicle fuel and are emitted intothe air when the fuel evaporates or passes through the engine unburned. Other toxics are emitted from theincomplete combustion of fuels or as secondary combustion products. Some air toxics also result fromengine wear or from impurities in oil or gasoline used in vehicles.


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The EPA regulations for vehicle engines and fuels will cause overall MSAT emissions to decline substantiallyover the next several decades. Based on current and future pollution control measures, an analysis ofnational trends with the EPA’s MOVES2010b model forecasts a combined reduction of 83 percent in the totalannual emission rate for priority MSATs from 2010 to 2050, while vehicle-miles of travel are projected toincrease by 102 percent (FHWA 2012).

FHWA provides guidance on how to analyze MSATs during NEPA documentation. The most recent

guidance is titled Interim Guidance Update on Mobile Source Air Toxics Analysis in NEPA, published onDecember 6, 2012.


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4. Methodology

The U.S. 50 Corridor East project is a Tier 1 EIS. “Tiering” for this process means that the work involved willbe conducted in two phases, or tiers, as follows:

Tier 1— A broad-based (i.e., corridor level) NEPA analysis and data collection effort. The goal of Tier 1 isto determine a general corridor location (not a roadway footprint). Data sources will include existingquantitative data, qualitative information, or both. Mitigation strategies (not necessarily specific mitigationactivities) and corridor-wide mitigation opportunities will be identified. Additionally, the Tier 1 EIS willidentify sections of independent utility (SIUs) and provide strategies for access management and corridorpreservation.

Tier 2— A detailed (i.e., project level) NEPA analysis and data collection effort. The goal of Tier 2 studieswill be to determine an alignment location for each SIU identified in Tier 1. Data sources will includeproject-level data, including field data collection when appropriate. Tier 2 studies will provide project-specific impacts, mitigation, and permitting for each proposed project.

Resource methodology overviews were developed to identify and document which resource evaluationactivities would be completed during the Tier 1 EIS, and which would be completed during Tier 2 studies.

These overviews are intended to be guidelines to ensure that the Tier 1 EIS remains a broad-based analysis,while clarifying (to the public and resource agencies) when particular data and decisions would be addressedin the tiered process.

These overviews were approved by FHWA and CDOT in 2005, and they were agreed upon by the resourceagencies during the project’s scoping process between February and April of 2006.

Each overview summarizes the following information for the given resource:

Relevant data or information sources—the types of corridor-level data that will be collected and thesources of those data

Data collection and analysis methodology—how the data collection and analysis will be completed

Project area—defined as one to four miles wide surrounding the existing U.S. 50 facility beginning in

Pueblo, Colorado, at Interstate 25 (I-25) and extending to the Colorado-Kansas state line (resources willbe reviewed within this band, and it is the same for all resources)

Effects—the type(s) of effect(s) to be identified

Mitigation options—how mitigation will be addressed

Deliverables—how the activities above will be documented

Regulatory guidance/requirements—a list of applicable laws, regulations, agreements, and guidance thatwill be followed during the review of the resources

These overviews were used by the project’s resource specialists as guidelines to ensure that their activ itieswere relevant to the Tier 1 decision (i.e., corridor location). As the resource specialists conducted their work,data sources or analysis factors were added or removed. The final actions of the resource specialists aredescribed below. The resource methodology overview for air quality is attached to this technicalmemorandum as Appendix A for reference only. Additionally, abbreviations and acronyms used in this report

are listed in Appendix B.

4.1. Relevant Data or Information SourcesThe following data and information sources were used for this analysis of air quality:

Colorado Climate Center (CCC), Natural Resources Conservation Service (NRCS), and WesternRegional Climate Center (WRCC)—regional and local meteorological conditions


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EPA and Colorado Department of Public Health and Environment(CDPHE)—current pollutant levels bycounty

EPA—NAAQS and attainment status by county

CDOT—current (2008) and projected future (2040) traffic volumes on U.S. 50 in southeastern Colorado

Additionally, air quality-sensitive receptors in the project area were identified. They include schools,churches, residences, hospitals, playgrounds, and other recreational facilities. Various sources were used to

locate these receptors. Schools were identified using the U.S. Department of Education’s Center forEducation Statistics. Residences were identified using municipal zoning ordinances from the communities inthe project area. All areas categorized as residential in those ordinances were assumed to includeresidences. Hospitals were located using a licensure database maintained by the CDPHE. Playgrounds andother recreational facilities were located using information from the city of Pueblo’s website (facilities inPueblo only), information from a previous U.S. 50 study, and a field review conducted as part of the Section4(f) analysis for the U.S. 50 Tier 1 EIS project. Receptors also were located using U.S. Department of Agriculture aerial photography.

4.2. Data Collection and Analysis MethodologyThe following tasks were completed during this review of air quality and are described in detail below (alltasks were completed on a county level for Pueblo, Otero, Bent, and Prowers counties unless otherwise

noted).

Collection and review of air quality emissions inventory data

Collection and review of air quality emissions monitoring data

Review of attainment status

Review of traffic volumes on U.S. 50

Identification of air quality-sensitive receptors (in the project area only)

Air emissions inventory data were obtained from a public database maintained by the CDPHE. Thisemissions information is broken out by area source, point source, highway vehicle, and off-highway vehicleemission categories based on the 2004 emissions inventory. These data provide a reasonable base fromwhich to compare potential project emissions. Emissions monitoring and attainment status data (i.e., NAAQSdata) were obtained from the EPA’s public database. These data are used in this analysis to evaluate

potential changes in air quality. Also, CDOT traffic data were obtained to evaluate how predicted (i.e., future)changes in traffic volumes on U.S. 50 could affect air quality in the project area. Air quality-sensitivereceptors were located to determine how the Build Alternatives could affect them.

4.3. Project AreaThe project area for the U.S. 50 Tier 1 EIS has been defined as one to four miles wide surrounding theexisting U.S. 50 facility and extending from Pueblo, Colorado, at I-25 to the Colorado-Kansas state line (.

Figure 1-1). The project area encompasses the study area limits, which is where the Tier 1 corridoralternatives considered by this project would be located.

The study area is 1,000 feet wide centered on the corridor alternatives, beginning on or near the existingU.S. 50 at I-25 in Pueblo, Colorado, and extending to just east of Holly, Colorado, in the vicinity of theColorado-Kansas state line. The limits of the project were approved by the lead agencies and other projectstakeholders during the U.S. 50 Tier 1 EIS’s scoping activities.


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4.4. EffectsThis analysis of air quality consisted of a qualitative assessment of whether the Build Alternatives wouldlikely cause a violation in the NAAQS in the project area. Potential effects to air quality-sensitive receptorsalso were considered.

4.5. Mitigation Options Air quality would not be affected by the U.S. 50 Tier 1 EIS because no construction-related activit ies wouldbe authorized. Therefore, mitigation options for the Build Alternatives will be evaluated as part of Tier 2studies.

4.6. DeliverablesThis Air Quality Technical Memorandum is the primary deliverable being produced for the U.S. 50 Tier 1 EISrelated to air quality issues.


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5. Existing Conditions

The following sections describe the climate, air quality status, and traffic conditions on U.S. 50 in Pueblo,Otero, Bent, and Prowers counties.

5.1. ClimateEastern Colorado lies within the rain shadow east of the Rocky Mountains. The climate of the Great Plainsgrasslands is a semi-arid regime with characteristic low relative humidity, abundant sunshine, infrequentrains and snow, moderate to high wind movement, and a large seasonal range in temperature (CCC 2007).Winters are cold and dry, and summers warm to hot. The mean annual temperature is approximately 54degrees Fahrenheit throughout most of the project area and ranges from roughly 52 degrees Fahrenheit atPueblo to 55 degrees at Las Animas (WRCC 2006). The average annual maximum temperature is nearly 72degrees Fahrenheit compared to an average annual minimum temperature of roughly 36 degrees (WRCC2006). Extreme summer temperatures can be above 100 degrees Fahrenheit, and extreme wintertemperatures can fall below zero degrees Fahrenheit (WRCC 2006).

The mean annual precipitation ranges from over 11 inches per year at La Junta to nearly 16 inches at Holly,

and the average mean is about 13 inches across the project area (WRCC 2006). Extreme fluctuations inannual precipitation occur, and have been recorded from a low of almost 4 inches at La Junta to a high of just over 29 inches at Holly. The majority of the precipitation (70 percent to 80 percent) occurs as rain from April through September. Periods of high winds occur in late February, March, and April. The frost-freeperiod ranges from 100 days at Pueblo to over 170 days at Holly (WRCC 2006). The moisture and soiltemperature regimes are described as ustic or as aridic and mesic (NRCS 2002).

5.2. Air QualityCDPHE air emissions inventory data for Pueblo, Otero, Bent, and Prowers counties is presented in Table5-1. Communities along U.S. 50 have industrial as well as agricultural-based economies. Thus, air quality isaffected by dust from local agricultural plowing, unpaved roads and open lands, highway and off-highwayvehicle emissions, commercial manufacturing, and industrial activities. As shown in Table 5-1, the major

producers of air emissions are highway and off-highway vehicles. Oxides of nitrogen (NOx) and SO2emissions also are attributed to point sources such as fuel combustion equipment at industrial facilities. Themajority of the particulate matter emissions are area source emissions, such as from agricultural activities.Biogenic sources, such as trees and vegetation, contribute to background emissions of nitrogen, CO, andvolatile organic compounds.


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Table 5-1. Air Emissions Inventory for Pueblo, Otero, Bent, and Prowers Countiesby Source Category (2004)

County Source CategoryTons per Year

CO NOX PM10 SO2 VOC Benzene

Pueblo

Area 5,600 300 7431 17 3,160 31

Point 3,292 8,625 946 14,486 1,114 10

Highway vehicles 34,208 3,227 82 96 2,193 82

Off-highway vehicles 9,222 659 68 16 720 20

Railroads 83 840 21 48 31 0

Biogenic 3,903 596 0 0 20,379 0

Subtotal 56,308 13,651 8,548 14,663 7,218 143

Otero

Area 1,756 80 2,225 8 618 9

Point 110 71 32 1 190 2

Highway vehicles 4,403 598 18 20 297 10


Railroads 27 278 7 16 10 0

Biogenic 2,991 482 0 0 14,875 0

Subtotal 10,813 1,632 2,296 48 16,173 26

Bent

Area 133 12 1,302 0 189 1

Point 141 194 29 1 22 1



Railroads 28 286 7 16 11 0

Biogenic 2,907 777 0 0 13,416 0

Subtotal 6,638 1,682 1,366 31 14,256 19

Prowers

Area 499 43 5,156 2 641 3

Point 441 586 234 4 198 1



Railroads 10 98 2 6 4 0

Biogenic 2,520 1,468 0 0 9,223 0

Subtotal 9,008 3,430 5,481 48 10,518 17

ALL TOTAL 82,767 20,395 17,691 14,790 48,165 205

CO = carbon monoxide

NO x = oxides of nitrogenPM 10 = respirable particulate matterSO2 = sulfur dioxide

VOC = volatile organic compoundsSource: CDPHE 2004

Additionally, Pueblo, Otero, Bent, and Prowers counties are currently designated as“unclassifiable/attainment” under the NAAQS (CAA 2003, part 81). Monitor value data for Pueblo andProwers counties are available from the EPA’s public database, but only for fine particulate matter (PM2.5)


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and respirable particulate matter (PM10). Other contaminants are not monitored currently in these counties. Asummary of these monitored values is presented in Table 5-2. Monitor value data are not available in theEPA’s database for Bent and Otero counties (i.e., ambient air is not currently monitored in these counties).The data in Table 5-2 show no exceedance of the NAAQS for PM2.5 and PM10.

Table 5-2. Monitored Values Summary for Pueblo and Prowers Counties

County Year98th Percentile24-hour Value

for PM2.5( g/m3)

AnnualMean Value

for PM2.5( g/m3)

2nd 24-hourValue for

PM10( g/m3)

AnnualMean Value

for PM10( g/m3)

Pueblo

1996 49 26

1997 56 27

1998 52 25

1999 13 6.8 51 25

2000 20 7.8 64 24

2001 19 8.5 63 25

2002 17 7.8 61 27

2003 17 7.6 64 25

2004 16 6.8 56 23

2005 13 7.2 50 22

2006 19 8.7 53 23

Prowers

1996 80 24

1997 98 23

1998 100 26

1999 145 29

2000 136 29

2001 133 31

2002 138 31

2003 120 29

2004 82 24

2005 110 21

2006 127 24

NAAQS 35 15.0 150 50

Blank entries = no monitoring data availablePM 2.5 = fine particulate matterPM 10 = respirable particulate matter

g/m3 = micrograms per cubic meter

Source: EPA 2007

Even though Lamar is not located in the project area, it was included here because the community isdesignated as “attainment/maintenance” under the NAAQS. In Lamar, particulate matter was monitored atlevels that violated pollutant standards in the 1980s, but this was primarily due to other sources of pollution,with minimal contribution from motor vehicle use. More recent violations occurred in 1996, 1999, and 2000due to high wind conditions. The state of Colorado determined, and the EPA agreed, that high wind eventscaused these violations, which would not have occurred otherwise (CDPHE 2001). In 2005, the EPAapproved a maintenance attainment plan documenting that the past problem had been remedied, the air


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quality standard had been met for 10 years, and no further violations were anticipated in the foreseeablefuture (EPA 2005).

Air quality-sensitive receptors in the project area were identified. The vast majority of these receptors arelocated within the cities and towns along U.S. 50. Very few receptors were identified outside these areas.This is because urban development in the Lower Arkansas Valley is concentrated within these municipalities.Land outside town generally is used for farming or ranching and only inhabited by the farmers and ranchers

who own the land.

Implementation of the Build Alternatives would likely be federally funded and considered regionallyimportant. Under those conditions, they would be required to undergo conformity determination. U.S. 50through the Lower Arkansas Valley is listed as a high priority for improved mobility and safety in theSoutheast Transportation Planning Region’s 2040 Regional Transportation Plan and the Pueblo AreaCouncil of Governments 2040 Long-Range Transportation Plan (PACOG 2015).

5.3. Traffic Conditions Along U.S. 50 in the Lower Arkansas Valley, emissions from motor vehicles are a major source of airpollution; however, emissions levels have never been high enough to cause a violation of air pollutionstandards. As shown in Figure 5-1, the average traffic volume on U.S. 50 was roughly 5,500 vehicles per day

(vpd) in 2011. This figure ranged widely from roughly 13,500 vpd in Pueblo to about 1,700 vpd from Holly tothe Colorado-Kansas state line. In contrast, I-25 through Pueblo averaged approximately 47,846 vpd in 2012(CDOT 2012).

Figure 5-1. Average Annual Daily Traffic on I-25 through Pueblo and on U.S. 50 in the LowerArkansas Valley (2011 and projected 2040)


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On average, traffic volumes are expected to rise by approximately 52 percent by 2040 (see Figure 5-1) alongthe U.S. 50 corridor. The traffic volumes on U.S 50 in Pueblo will increase by 40 percent adding just over5,500 vpd between 2011 and 2040. The most substantial increase in vpd is expected to occur in the town ofLa Junta. Traffic through La Junta is projected to increase by 60 percent, adding 6,000 vpd (CDOT 2012).Despite these increases in traffic, future volumes are not expected to cause a violation in pollution standardsin any of the communities along the U.S. 50 corridor.

Additionally, traffic data show that nearly 12 percent of the vehicles driving on U.S. 50 in 2012 werecommercial trucks. This proportion varied widely along the corridor, from six percent in Pueblo to more than25 percent near the Colorado-Kansas state line (CDOT 2012). This is important because commercial trucksgenerally have diesel engines, and these engines produce emissions that are considered a pollutant ofconcern for sensitive sites, such as schools, hospitals, and elder care facilities. The percentage ofcommercial trucks on the highway is expected to remain about the same through 2040 (CDOT 2012).However, while a sizable percentage of the vehicles driving on U.S. 50 are commercial trucks, vehicle-related pollution has not been an issue along U.S. 50 in the Lower Arkansas Valley, and it is not expected tobe an issue through 2040. Additionally, recent advances in diesel technology have already reducedemissions from these types of engines, and this trend is expected to continue into the future (TruckingIndustry Mobility and Technology Coalition [TIMTC] 2010).


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6. Effects

The following sections discuss the potential of the No-Build Alternative and the Build Alternatives to affect airquality in the project area.

6.1. No-Build AlternativeUnder the No-Build Alternative, only minor and isolated construction would occur. Routine maintenance andrepairs would be made as necessary to keep U.S. 50 in usable condition, including standard overlays andrepairs of weather- or crash-related damage. Additionally, smaller scale improvements may be undertaken,such as short passing lanes and other minor safety improvements. However, no direct effects to air qualityare expected.

Several conditions will continue to affect air quality in the Lower Arkansas Valley, including the following:

Between 2011 and 2040, average traffic volumes on U.S. 50 through project corridor are expected toincrease by approximately 52 percent, so there will be more motor vehicles producing emissions (CDOT2012). However, continued improvements in fuel and motor vehicle technologies are expected to result

in lower emission rates for engine- and exhaust-related criteria pollutants, MSATs, and greenhousegases (GHGs) in the future. These reductions could offset some of the expected emissions increasesfrom additional traffic.

Non-vehicle-related sources of air pollution will continue to affect air quality. Feedlots, which generatelarge amounts of animal waste in a concentrated area, are one of these sources. There are eightfeedlots located along or near U.S. 50 in the Lower Arkansas Valley, and several of them are locateddirectly adjacent to the highway (Tranel 2008).

Communities are actively pursuing economic diversification, which could include new emission sources(i.e., more industrial activity). However, assuming that any new emission generators comply withestablished air quality regulations, there is no reason to anticipate any air quality problems stemmingfrom these facilities for the foreseeable future.

Soils in the area are sensitive to disturbances that cause airborne dust and debris. Highway constructionactivities will temporarily increase the number of sources of dust. These impacts can be reduced with the

use of spraying and other dust control measures.

6.2. Build AlternativesThe Build Alternatives consist of constructing a four-lane expressway on or near the existing U.S. 50 fromI-25 in Pueblo, Colorado, to approximately one mile east of Holly, Colorado. There are a total of 30 Build Alternatives. In Pueblo, three Build Alternatives are proposed that either improve U.S. 50 on its existingalignment and/or reroute it to the north to utilize SH 47. East of Pueblo, the remaining 27 Build Alternativesare divided into nine between-town alternatives and 18 around-town alternatives. The nine between-townalternatives improve U.S. 50 on its current alignment, with the exception of near Fort Reynolds, where thereis an alternative to realign the roadway to the south. The 18 around-town alternatives propose relocatingU.S. 50 from its current through-town route at Fowler, Manzanola, Rocky Ford, Swink, La Junta, Las Animas,Granada, and Holly. Figure 6-1 provides an overview of the Build Alternatives as proposed.

In the aforementioned eight communities, the average traffic volume in 2011 was just over 5,600 vpd (CDOT2012). In 2040, this figure is expected to rise by approximately 56 percent to just over 8,800 vpd (CDOT2012).The Build Alternatives would move a portion of this traffic out of town, potentially improving air qualityin these downtown areas. Many of these communities have expressed a desire to revitalize their downtowns,making them more suitable for pedestrians (CDOT 2006a). The Build Alternatives could help thosecommunities reach this goal by improving air quality in these areas.


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Although traffic volumes on U.S. 50 in the project area are expected to increase up to 52 percent, theincreased number of vehicles averages 8,800 vpd (CDOT 2012). These volumes are not expected to causea violation in pollution standards in any of the communities along U.S. 50 in the Lower Arkansas Valley.

Figure 6-1. Build Alternatives Overview


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Air quality effects from the Build Alternatives would include air contaminant emissions from combustion offuel in vehicles, idling of vehicles, re-entrained road dust, and fugitive dust generated by constructionactivities during Tier 2 studies. Rerouting U.S. 50 to around-town locations at eight municipalities wouldremove emissions originating from traffic on the highway, including commercial trucks, away from populatedareas in town to the less populated periphery of these communities.

6.2.1. Sensitive ReceptorsMost sensitive receptor sites, such as schools, hospitals,and elder care facilities, are located in town, so the Build Alternatives would move traffic away from these locations.However, the Build Alternatives would move the highwaycloser to sensitive receptors at locations in Alternative 2:Fort Reynolds Realignment, Alternative 2: Swink South, Alternative 2: La Junta South, Alternative 1: Las AnimasNorth, and Alternative 1: Holly North. With the exception ofalternatives in Swink and Holly, the Build Alternativeswould locate the highway farther than 1,000 feet fromsensitive receptor locations. Impacts at Swink and Hollyare described below.

Section 10: Swink

Alternative 1: Swink North would reroute U.S. 50 traffic farther away from the school complex than it is today,potentially reducing pollutant levels at the site. Alternative 2: Swink South would reroute U.S. 50 traffic closerto the public school complex, which includes an elementary school and a junior-senior high school. Schoolsgenerally are considered sensitive sites in air quality analyses because of the large number of children, whomay be more susceptible to the effects of pollution. While this alternative does have the potential to increasepollutant levels (caused by vehicle emissions) above the levels experienced today, this change is notexpected to increase pollutant levels enough to exceed EPA standards at this location.

Section 20: Hol ly

Alternative 1: Holly North would reroute U.S. 50 traffic closer to the Holly Junior-Senior High School and

would potentially increase pollutant levels (caused by vehicle emissions) from the levels experienced today. Alternative 2: Holly South would move the highway farther from the school than it is today, potentiallyreducing pollutant levels at the site.

6.2.2. Construction ActivitiesConstruction activities resulting from Tier 2 studies are expected to produce diesel particulate, nitrogenoxide, and hydrocarbon emissions from the use of construction equipment and dust emissions from grounddisturbance. These emissions would result in minor, short-term effects on air quality in the immediate vicinityof the activities. However, it also is expected that clean vehicle technologies would be applied to constructionequipment. Therefore, it is likely that the equipment used to construct the Build Alternatives in the futurewould produce fewer emissions than today’s equipment. More specific effects to air quality by construction-related activities should be identified during Tier 2 studies.

Additionally, this analysis includes the EPA’s assessment of the respirable particulate matter maintenanceplan for the City of Lamar (revised on December 20, 2012). This review was intended to determine theadequacy of the emissions budgets for respirable particulate matter contained in the maintenance plan forpurposes of conformity with the state implementation plan. The conformity rule spells out limited technicaland administrative criteria that the EPA must use in determining adequacy of submitted emissions budgets.Based on the plan submittal, the EPA determined that these criteria were satisfied, and the budgets wereadequate for transportation conformity purposes (EPA 2012).

Potential Effect on Air Quality

The Build Alternatives would moveU.S. 50 to around-town locations ineight communities: Fowler, Manzanola,Rocky Ford, Swink, La Junta, Las Animas, Granada, and Holly. Thiswould move traffic, and resultingemissions, from populated areas intown to less populated areas outside oftown.


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In the Lamar maintenance plan, Colorado established a new mobile source emissions budget of 764 poundsper day for the year 2025 and beyond (EPA 2012). The new mobile source emissions budget is the total ofthe 2025 mobile source PM10 emissions budget and includes emissions from vehicle exhaust, highways,paved arterial and local roads, and gravel roads. The EPA's approval of 764 pounds per day for Lamar asthe budget for this area means that this value must be used for conformity determinations for 2025 andbeyond. This information will be considered during Tier 2 studies.

The purpose of the U.S. 50 Tier 1 EIS is to improve safety and mobility for local, regional, and long-distanceusers of U.S. 50 through the Lower Arkansas Valley. It is important to state that existing mobility issues onthe highway are not related to traffic congestion. There are no traffic congestion problems on this portion ofthe highway at this time, and congestion is not expected to become an issue in the foreseeable future. Addressing existing safety and mobility issues on the highway will be accomplished by correcting roadwaydeficiencies, while balancing the mobility and access needs of these users and providing flexibility to meetfuture travel demands. This project has been determined to generate minimal air quality effects for criteriapollutants regulated by the Clean Air Act of 1990 (and its amendments) and has not been linked with anyspecial concerns about MSATs. As such, this project will not result in changes in traffic volumes, vehicle mix,basic project location, or any other factor that would cause an increase in effects from MSATs from theproject when compared to the No-Build Alternative.

Moreover, EPA regulations for vehicle engines and fuels will cause overall MSAT emissions to decline

significantly over the next several decades (FHWA 2009). Based on regulations now in effect, an analysis ofnational trends with the EPA’s MOBILE6.2 model forecasts a combined reduction of 72 percent in the totalannual emission rate for priority MSATs from 1999 to 2050, while vehicle miles of travel (vmt) are projectedto increase by 145 percent. This will reduce both the background level of MSATs as well as the possibility ofeven minor MSAT emissions from this project.


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7. Mitigation Strategies

Since the ultimate roadway footprint would be identified during Tier 2 studies, this Tier 1 analysis cannotidentify specific air quality effects from the Build Alternatives. However, the following mitigation strategieshave been developed to ensure that negative effects are minimized during Tier 2 studies.

Dust control—techniques include watering the areas disturbed by construction

CDOT air quality directive—CDOT should implement the appropriate air quality mitigation measuresincluded in CDOT Air Quality Policy Directive #1901


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8. References

City of La Junta. Engineering Department. Zoning Ordinance. 2006. Print.

City of Pueblo. Pueblo Municipal Code. Zoning Ordinance. Web. 19 Jun. 2006. .

City of Rocky Ford. Planning Commission. Zoning Ordinance. 2006. Print.

Clean Air Act of 1990 (CAA) Regulations. 40 CFR 50-99. Jul 1, 2003.

Colorado Climate Center (CCC). Climate Information. Web. Jan. 2007. .

Colorado Department of Public Health and Environment (CDPHE). Air Pollution Control Division. DraftRevised PM 10 Maintenance Plan for the Lamar Attainment/Maintenance Area, Colorado. Denver,CO: CDPHE, Nov. 2001. Print.

Colorado Department of Public Health and Environment (CDPHE). Hospitals in Colorado. Web. 10 Oct.2006. .

Colorado Department of Public Health and Environment (CDPHE). Technical Services Program, Air QualityReporting System, Emissions Inventory . 2004. Web. 2007. .

Colorado Department of Transportation (CDOT). A Corridor Selection Study: A Plan for U.S. 50 . ColoradoSprings, CO: Colorado Department of Transportation (CDOT) Region 2, Sep. 2003. Print.

Colorado Department of Transportation (CDOT). U.S. 50 Tier 1 EIS Community Workshops Report. Colorado Springs, CO: Colorado Department of Transportation (CDOT) Region 2, Aug. 2006.[CDOT 2006a]

Colorado Department of Transportation (CDOT). U.S. 50 Tier 1 EIS Section 4(f) Resources Evaluation DataCollection Summary. Colorado Springs, CO: Colorado Department of Transportation (CDOT) Region2, Sep. 2006 and Oct. 2006. [CDOT 2006b]

Colorado Department of Transportation (CDOT). Draft Air Quality Policy Directive #1901. 20 Apr. 2009. Print.

Colorado Department of Transportation (CDOT). Future Traffic Volumes of SH050B from MP 315 to MP 467. Web. 2 Feb. 2010. . [CDOT 2010a]

Colorado Department of Transportation (CDOT). Traffic Information for I-25 from MP 93 to MP 104 (Pueblo). Web. 15 Feb. 2010. . [CDOT 2010b]

Colorado Department of Transportation (CDOT). Traffic Information for SH050B from MP 315 to MP 467. Web. 2 Feb. 2010. . [CDOT 2010c]

Colorado Department of Transportation (CDOT). Online Transportation Information System (OTIS) Data for2012 . Web. Mar. 2014. . [CDOT 2012]

Council on Environmental Quality (CEQ). Regulations for Implementing NEPA. 40 CFR Parts 1500-1508.1978.

http://ccc.atmos.colostate.edu/%20climateofcolorado.phphttp://ccc.atmos.colostate.edu/%20climateofcolorado.phphttp://dtdapps.coloradodot.info/otishttp://dtdapps.coloradodot.info/otishttp://ccc.atmos.colostate.edu/%20climateofcolorado.phphttp://ccc.atmos.colostate.edu/%20climateofcolorado.php


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National Center for Education Statistics (NCES). Public School Districts, 2003-2004 School Year. Web. 11Oct. 2006. .

National Environmental Policy Act of 1969 (NEPA) Regulations. 23 CFR 771. 1987. Print.

Natural Resources Conservation Service (NRCS).Climate Data for WETS Stations: Holly, CO4076; Lamar,CO4770; Las Animas, CO4834; Pueblo WSO AP, CO6740; and Rocky Ford 2 SE, CO7167. 2002.

Web. Apr. 2006. .

Otero County. Land Use Department. Zoning Ordinance. 2006. Print.

Pueblo Area Council of Governments (PACOG 2015). 2040 Long-Range Transportation Plan. Pueblo, CO:PACOG, 2Nov. 2015. Web.http://www.pacog.net/

Pueblo County. Planning and Zoning Commission. Zoning Ordinance. Web. 19 Jun. 2006. .

Southeast Transportation Planning Region (SE TPR). 2035 Regional Transportation Plan. Jan. 2008.

Town of Fowler. Planning and Zoning Board. Zoning Ordinance. 2006. Print.

Town of Manzanola. Zoning Ordinance. 2006.

Town of Swink. Zoning Ordinance. 2006.

Tranel. J. Identification of Highest and Best Agricultural Use of Non-Urbanized Land in the Project Area. Lafayette, CO: WYCO Associates, LLC. 24 Apr. 2008. Print.

Trucking Industry Mobility and Technology Coalition (TIMTC). Green Trucks: The View from the Road. Webinar presented on 11 Feb. 2010. .

U.S. Congress. Clean Air Act of 1990 (CAA). 42 USC 7609. 1990.

U.S. Congress. National Environmental Policy Act of 1969 (NEPA). 42 USC 4321-4347. 1969.

U.S. Department of Agriculture (USDA) Aerials. USDA Aerial Photography Field Office. Flown Jun. 2004.

U.S. Department of Transportation (USDOT). Federal Highway Administration (FHWA). Interim GuidanceUpdate on Mobile Source Air Toxic Analysis in NEPA Documents. 6 Dec. 2012. Print.

U.S. Environmental Protection Agency (EPA). Adequacy Status of the Lamar and Steamboat Springs,Colorado PM 10 Maintenance Plans for Transportation Conformity Purposes. 2002. Web. 2007..

U.S. Environmental Protection Agency (EPA). AirData. Web. 2007. .

U.S. Environmental Protection Agency (EPA). “ Approval and Promulgation of Air Quality ImplementationPlans; CO; PM10 Designation of Areas for Air Quality Planning Purposes, Lamar; StateImplementation Plan Correction.” Federal Register. 70 No 233: 72597-72598. 6 Dec. 2005. Print.

U.S. Environmental Protection Agency (EPA). National Ambient Air Quality Standards (NAAQS). Web. Feb.2009. .


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U.S. Environmental Protection Agency (EPA). Office of Air Quality Planning and Standards. Memorandum:Boundary Guidance on Air Quality Designations for the 8-Hour Ozone National Ambient Air QualityStandards. 28 Mar. 2000. Print.

U.S. Environmental Protection Agency (EPA). “Transportation Conformity Rule Amendments.” FederalRegister. 69 (126). 1 Jul. 2004.

Western Regional Climate Center (WRCC). Climate of Colorado Narrative and State Temperature andPrecipitation Data. 2006. Web. Jan. 2007. .

http://www/wrcc/dri.eduhttp://www/wrcc/dri.edu


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Appendices


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Appendix A. Resource MethodologyOverview for Air Quality

This resource methodology overview is attached to this technical memorandum for reference only. The lead

agencies for the U.S. 50 Tier 1 EIS (CDOT and FHWA) drafted resource methodology overviews to identifyand document which resource evaluation activities would be completed during the Tier 1 EIS, and whichwould be completed during Tier 2 studies. These overviews were intended to be guidelines to ensure thatthe Tier 1 EIS remained a broad-based analysis, while clarifying (to the public and resource agencies) whenparticular data and decisions would be addressed in the tiered process. These overviews were approved bythe lead agencies, and they were agr eed upon by the resource agencies during the project’s scopingprocess. They were used subsequently by the project’s resource specialists as guidelines to ensure that theiractivities were relevant to the Tier 1 (corridor location) decision.


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Table A-1. Resource Methodology Overview for Air Quality

MethodologyOverview

Air Quality

Tier 1 Tier 2

Relevant Data/Information

Sources

Local meteorological conditions andpollutant levels

NAAQS/attainment status

Update Tier 1 data collection sufficientlyfor standard NEPA documentation

Collectionand/or

AnalysisMethodology

Collect existing data related to attainmentstatus within the corridor

Document regulatory requirements,including a summary of potentialhealth effects of criteria pollutants

Document local meteorologicalconditions and/ or quality monitoreddata in study area

Identify attainment status of townswithin corridor

Outline conformity requirements forprojects proposed in maintenanceareas

Project Area

One to four miles wide surrounding the

existing U.S. 50 facility beginning at I-25in Pueblo to the vicinity of the Colorado-Kansas state line

Non-attainment or maintenance areas

within Tier 2 specific SIU corridorboundaries

Impacts

Identify maintenance areas within thestudy area and qualitatively determine ifthe proposed action would likely cause ornearly cause a violation in the NAAQS

Perform qualitative PM10 analysis

Summarize attainment status-relatedinformation

Develop acceptable methodology foranalysis, coordinating between AirPollution Control Division and EPA

Air Pollution Control Division toperform regional and corridor analysiswith EPA coordination

Particulate emissions (PM10) from

motor vehicles (There is no EPA-approved hot spot model for PM10.However, FHWA has developedqualitative guidance for evaluating thelocalized impacts of mobile sourcePM10 emissions)

MitigationOptions

None expected Methods to reduce airborne dust duringconstruction

Deliverables

Air Quality Technical Memorandumoutlining air quality attainment status andrecommendations for projects to beincluded in the State Implementation Planmodeling

Air Quality Technical Report outlining thepotential air quality impacts as appropriatefor Tier 2 SIUs level of NEPAdocumentation and a determination ofconformity for projects located in

maintenance areas

RegulatoryGuidance/

Requirements

Transportation Equity Act of the 21st Century, Sections 1110 and 6101

FHWA Technical Advisory T6640.8a

Applicable SIP Plan

Clean Air Act of 1990 (42 USC 7400; 23 USC 109(j); 23 USC 149; 23 USC 102(a);and 23 USC 110(c))

40 CFR Parts 51 and 93

23 CFR 770


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Appendix B. Abbreviations and Acronyms

CAA Clean Air Act of 1990

CCC Colorado Climate Center

CDOT Colorado Department of Transportation

CDPHE Colorado Department of Public Health and Environment

CEQ Council on Environmental Quality

CFR Code of Federal Regulations

CO Carbon monoxide

EA Environmental Assessment

EPA U.S. Environmental Protection Agency

FHWA Federal Highway Administration

FONSI Finding of No Significant Impact

GHG Greenhouse gas

MAP-21 Moving Ahead for Progress in the 21st Century Act of 2012

MSAT Mobile source air toxic

NAAQS National Ambient Air Quality Standards

NEPA National Environmental Policy Act of 1969

NO2 Nitrogen dioxide

NOx Oxides of nitrogen

NRCS Natural Resources Conservation Service

O3 Ozone

Pb Lead

PM2.5 Fine particulate matter

PM10 Respirable particulate matter

SH State Highway

SIU Section of independent utility

SO2 Sulfur dioxide

TIMTC Trucking Industry Mobility and Technology Coalition

U.S. 287 U.S. Highway 287

U.S. 50 U.S. Highway 50 U.S. 50 Tier 1 EIS U.S. Highway 50 Tier 1 Environmental Impact Statement

USC United States Code

vmt Vehicle miles traveled

vpd Vehicles per day

WRCC Western Regional Climate Center


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Appendix C. National Ambient Air QualityStandards

Criteria PollutantsThe EPA has established NAAQS for six principal pollutants, or “criteria” pollutants, which are listed inTable C-1 below and described in more detail below. Primary standards set limits to protect public health,including the health of “sensitive” populations such as people with asthma, children, and the elderly.Secondary standards set limits to protect public welfare, including protection against decreased visibility anddamage to animals, crops, vegetation, and buildings.

Table C-1. NAAQS Criteria Pollutants

Criteria Pollutant Primary Standards Averaging Times Secondary Standards

CO

(Carbon monoxide)

9 ppm (10 mg/m3) 8-hour 1 None

35 ppm (40 mg/m3) 1-hour 1 None

Pb(Lead)

0.15 µg/m3 Quarterly Average Same as Primary

NO2

(Nitrogen dioxide)

0.053 ppm (100 µg/m3) Annual (Arithmetic

Mean)Same as Primary

100 ppb 1-hour 3 None

PM10

(Respirable particulatematter)

Revoked2 Annual (Arithmetic

Mean)

150 µg/m3 24-hour 3a Same as Primary

PM2.5

(Fine particulate matter)

12 µg/m3 Annual4 (Arithmetic

Mean)15 µg/m3 Annual4

35 µg/m3 24-hour 5 Same as PrimaryO3

(Ozone)

0.075 ppm 8-hour 6 Same as Primary

SO2

(Sulfur dioxide)

75 ppb7 1-hour

— 3-hour 0.5 ppm1 1Not to be exceeded more than once per year.2 The annual average standard for PM 10 was revoked by EPA in a rule-making in September 2006. The previousstandard was 50 µg/m3.3This standard is obtained from the 98 th percentile, averaged over three years.3aNot to be exceeded once per year on average over 3 years.4To attain this standard, the three-year average of the annual arithmetic mean PM 2.5 concentrations from single ormultiple community-oriented monitors must not exceed 15 µg/m3.5

This standard was revised from 65 to 35 µg/m

3

by EPA in a rule-making in September 2006, and will be implementedover a lengthy period. To attain this standard, the three-year average of the 98th percentile of 24-hour concentrations ateach population-oriented monitor within an area must not exceed 35 µg/m3.6 EPA lowered the ozone standard from 0.08 ppm to 0.075 ppm on March 12, 2008. To attain this standard, the 3-yearaverage of the fourth-highest daily maximum 8-hour ozone average concentrations measured at each monitor within anarea over each year must not exceed 0.075 ppm.7 This standard was set in a ruling on June 2, 2010. It will be measured from the 99th percentile of 1-hour daily maximumconcentrations averaged over three years.Source: EPA 2013 (40 CFR part 50)

http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#2http://www.epa.gov/air/#2http://www.epa.gov/air/#2http://www.epa.gov/air/#2http://www.epa.gov/air/#2http://www.epa.gov/air/#2http://www.epa.gov/air/#3http://www.epa.gov/air/#3http://www.epa.gov/air/#3http://www.epa.gov/air/#4http://www.epa.gov/air/#4http://www.epa.gov/air/#4http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#4http://www.epa.gov/air/#3http://www.epa.gov/air/#2http://www.epa.gov/air/#2http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#1http://www.epa.gov/air/#1


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Carbon MonoxideCO is a colorless, odorless, tasteless gas. It may temporarily accumulate at harmful levels, especially in calmweather during winter and early spring, when fuel combustion reaches a peak and CO is chemically morestable due to the low temperatures. CO usually dissipates quickly over a large area, posing minimal threat tohuman health. Transportation activities, indoor heating, and open burning are among the anthropogenic (i.e.,manmade) sources of CO.

Nitrogen DioxideNO2, nitric oxide, and nitrate radical are collectively called NOx. These three species are interrelated, oftenchanging from one form to another in chemical reactions. NO2 is the species commonly measured in ambientair monitors. NOx generally are emitted in the form of nitric oxide, which is oxidized to NO2. The principalmanmade source of NOx is fuel combustion in motor vehicles and power plants. Reactions of NOx with otheratmospheric chemicals can lead to the formation of ozone and acidic precipitation.

OzoneGround-level ozone is a secondary pollutant, formed from daytime reactions of NOx and volatile organiccompounds rather than being directly emitted by natural and anthropogenic sources. Volatile organiccompounds, for which no NAAQS are established, are released in industrial processes and from evaporationof organic liquids, such as gasoline and solvents.

Fine Particulate Matter and Respirable Particulate MatterParticulate matter is separated into two different sizes for purposes of the NAAQS: fine particulate matterand respirable particulate matter. Respirable particulate matter is considered inhalable and fine particulatematter is considered to be in the respirable range, meaning these particles can reach the alveolar region ofthe lungs and penetrate deeper than respirable particulate matter. There are many sources of particulatematter, both natural and manmade, including dust from construction activities, industrial activities, andcombustion of fuels.

LeadDominant industrial sources of lead emissions include waste oil and solid waste incineration, iron and steelproduction, lead smelting, and battery and lead alkyl manufacturing. The lead content of motor vehicle

emissions, which was the major source of lead in the past, has significantly declined with the widespread useof unleaded fuel.

Sulfur DioxideSO2 is emitted in natural processes, such as volcanic activity, and by anthropogenic sources such ascombustion of fuels containing sulfur, sulfuric acid manufacturing, etc. SO2 emissions in the atmosphere canlead to the formation of acidic precipitation (i.e., acid rain).

National Ambient Air Quality Standards Compliance (Attainmentvs. Non-Attainment)The Clean Air Act of 1990 also requires the EPA to assign a designation for each area of the United States

regarding compliance with the NAAQS. The EPA categorizes the level of compliance or noncompliance asfollows:

Attainment—an area that meets the NAAQS for any pollutant

Maintenance—an area that currently meets the NAAQS, but has previously been out of compliance

Non-attainment—an area that does not meet the NAAQS or that contributes to ambient air quality in anearby area that does not meet the NAAQS.

Unclassifiable—any area that cannot be classified on the basis of available information as meeting or notmeeting the NAAQS.


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The EPA delegates authority for air quality monitoring and compliance to the Colorado Air Quality ControlCommission. The CDPHE takes the lead in air quality planning and the development of air quality-relatedstrategies, as well as specific programs to reduce air contaminant emissions.


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